Salas hotrodded blue DCB1 build

Will try if this works:

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The leds are red, does not look that way through the fluorescent lamp om my desk
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The raw power supply on a separate board
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Separate heatsink with the four fets
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The transformer
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Protector board in prebuild testing phase, based on upc1237

Don't mind the messy wiring, will tidy that up when I build it into it's case. This will be a house formerly owned by a sony cdp, with a black wooden front
 
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Hmm... looks like a 50VA transformer. Check its temperature is not unacceptable and secondary voltage is not low now and on 750mA increment. We don't want less than 5VDC difference between raw DC on the main filter caps to reg out DCV.

Certainly shorten the extension cabling to the MOSFETS and better install the gate stopper resistors directly to their gate pins. Use short legs on the Russian 0.22uF green capacitors too.

The sink maybe OK for more hot rod given the 12V+12V moderate voltage Tx.

The whole thing is going to sound even preciser after you will put it together tightly with minimum and twisted wiring (where it applies).

Good luck and let us see it boxed up when finished.
 
I just added 10R in parallel on the negative side. Voltage measured over the 1R resistor are 0,466V on the positive, and 0,448 on the negative side. Temperature of the heatsink is now about 6 degrees higher and stabilized at 48 degrees Celcius.

Main filter caps are 10.000uF

The wiring to the fets on the heatsink will be 1.5 mm solid core, so must be done when all is mounted in the case to end up without tension.
Thanks for the tip about the gate stoppers, this prevents the fets from picking up interference that feeds into the gate? I will move these resistors!

The temperature of the transformer is 32 degrees now. The only alternative that I have is a 2x18V, 2x 3,33A. Would that be better, even if that means lowering the ccs current to keep the heat down?
 
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What 1R resistors? Those under JFETS? Or some extra series current test ones? Use 0.1 Ohm if so.

Gate stoppers are like grid stoppers. The less stray inductance between them and the pin they drive is the more beneficial.

+/-10.000uF are good.

Don't go over 65C on sinks or 55C transformer when boxed up and the lid is on. So judge your max current based on passable temperature. Judge it like a class A amp for that and components temp ratings.
 
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The 12+12 VAC Tx is good for keeping the CCS MOSFETS heat contribution low if the DC rectified voltage is at least 5V higher than the regs output level. No more than 15+15 VAC is practical under such bias conditions. More Vin-Vout makes the MOSFETS less capacitive but more current is the main benefit upping their gfs (transconductance).
 
Yes, the ones under the jfets. Aren't they meant for this purpose?

I am not a tube guy, but the rest of the explaination makes sense:D

Raw dc output is about 16.2V on both sides, so still ok I guess.

So the 2x12V is going to stay. Will try eventually to find a larger one, as they Always sound nicer for reasons unknown to me...
 
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The ones under the JFETS are to know what current runs in each voltage reference (5 LEDS group) for serving two tentative purposes. A. Extending the voltage output for other uses than 10V for DCB1. B. Matching mania.:D

*The voltage drop should be indicating few mA on those 1 Ohm test points.
 
Joining that mania:

Measuring the voltage on the positive side gives me 1,556V/2,9191R=533mA
Doing the same on the negative with 20R extra in parallel gives me 1,355V/2,5474R=532mA
Should be in the ballpark.

I will never match, but my parts will :)

Oh, about that 0.22 cap, it is just an expirimental placement to see if it brings me anything. I could not measure or hear the difference. Will check later if a large electrolytic works. Would a FC cap 330uF from Panasonic work, or better try 2200uF low ESR from Yageo. I don't have any values in between right now...
 
Today, after working a year without problem my DCB burned something, I felt a burning smell and I stopped it.. After I opened the lid I saw burned CCS resistor on the V + side. After I changed the resistor with a new one 3LED group on the V + does not shine. Where to look for the problem?
Thanks